Tags: Locomotive.
Union Pacific 3985 or UP 3985 is a four-cylinder simple articulated 4-6-6-4 Challenger-type steam locomotive owned by Union Pacific Railroad. It was built in 1943 by the American Locomotive Company of Schenectady New York. The locomotive is one of only two of the original 105 Union Pacific Challengers in existence the other being UP 3977 on static display in North Platte Nebraska. It is currently the largest & heaviest operational steam locomotive in the world.
